Recently, a number of philosophers of biology have endorsed views about random drift that, we will argue, rest on an implicit assumption that the meaning of concepts such as drift can be understood through an examination of the mathematical models in which drift appears. They also seem to implicitly assume that ontological questions about the causality of terms appearing in the models can be gleaned from the models alone. We will question these general assumptions by showing how the same equation (...) — the simple 2 = p2 + 2pq + q2 — can be given radically different interpretations, one of which is a physical, causal process and one of which is not. This shows that mathematical models on their own yield neither interpretations nor ontological conclusions. Instead, we argue that these issues can only be resolved by considering the phenomena that the models were originally designed to represent and the phenomena to which the models are currently applied. When one does take those factors into account, starting with the motivation for Sewall Wright’s and R.A. Fisher’s early drift models and ending with contemporary applications, a very different picture of the concept of drift emerges. On this view, drift is a term for a set of physical processes, namely, indiscriminate sampling processes. (shrink)
This paper considers recent heated debates led by Jerry A. Coyne andMichael J. Wade on issues stemming from the 1929–1962 R.A. Fisher-Sewall Wrightcontroversy in population genetics. William B. Provine once remarked that theFisher-Wright controversy is central, fundamental, and very influential.Indeed,it is also persistent. The argumentative structure of therecent (1997–2000) debates is analyzed with the aim of eliminating a logicalconflict in them, viz., that the two sides in the debates havedifferent aims and that, as such, they are talking past each other. (...) Given aphilosophical analysis of the argumentative structure of the debates,suggestions supportive of Wade's work on the debate are made that areaimed, modestly, at putting the persistent Fisher-Wright controversy on thecourse to resolution. (shrink)
According to Philip Kitcher, scientific unification is achieved via the derivation of numerous scientific statements from economies of argument schemata. I demonstrate that the unification of selection phenomena across domains in which it is claimed to occur--evolutionary biology, immunology and, speculatively, neurobiology--is unattainable on Kitcher's view. I then introduce an alternative method for rendering the desired unification based on the concept of a mechanism schema. I conclude that the gain in unification provided by the alternative account suggests that Kitcher's view (...) is defective. (shrink)
: Where there are cases of underdetermination in scientific controversies, such as the case of the molecular clock, scientists may direct the course and terms of dispute by playing off the multidimensional framework of theory evaluation. This is because assessment strategies themselves are underdetermined. Within the framework of assessment, there are a variety of trade-offs between different strategies as well as shifting emphases as specific strategies are given more or less weight in assessment situations. When a strategy is underdetermined, scientists (...) can change the dynamics of a controversy by making assessments using different combinations of evaluation strategies and/or weighting whatever strategies are in play in different ways. Following an underdetermination strategy does not end or resolve a scientific dispute. Consequently, manipulating underdetermination is a feature of controversy dynamics and not controversy closure. (shrink)
Population genetics attempts to measure the influence of the causes of evolution, viz., mutation, migration, natural selection, and random genetic drift, by understanding the way those causes change the genetics of populations. But how does it accomplish this goal? After a short introduction, we begin in section (2) with a brief historical outline of the origins of population genetics. In section (3), we sketch the model theoretic structure of population genetics, providing the flavor of the ways in which population genetics (...) theory might be understood as incorporating causes. In sections (4) and (5) we discuss two specific problems concerning the relationship between population genetics and evolutionary causes, viz., the problem of conceptually distinguishing natural selection from random genetic drift, and the problem of interpreting fitness. In section (6), we briefly discuss the methodology and key epistemological problems faced by population geneticists in uncovering the causes of evolution. Section (7) of the essay contains concluding remarks. (shrink)
: This paper explores the calibration of laboratory models in population genetics as an experimental strategy for justifying experimental results and claims based upon them following Franklin (1986, 1990) and Rudge (1996, 1998). The analysis provided undermines Coyne et al.'s (1997) critique of Wade and Goodnight's (1991) experimental study of Wright's (1931, 1932) Shifting Balance Theory. The essay concludes by further demonstrating how this analysis bears on Diamond's (1986) claims regarding the weakness of laboratory experiments as evidence, and further how (...) the calibration strategy fits within Lloyd's (1987, 1988) account of the confirmation of ecological and evolutionary models. (shrink)
Sewall Wright's adaptive landscape is the most influential heuristic in evolutionary biology. Wright's biographer, Provine, criticized Wright's adaptive landscape, claiming that its heuristic value is dubious because of deep flaws. Ruse has defended Wright against Provine. Ruse claims Provine has not shown Wright's use of the landscape is flawed, and that, even if it were, it is heuristically valuable. I argue that both Provine's and Ruse's analyses of the adaptive landscape are defective and suggest a more adequate understanding of it.
In a small handful of papers in theoretical population genetics, John Gillespie (2000a, 2000b, 2001) argues that a new stochastic process he calls "genetic draft" is evolutionarily more significant than genetic drift. This case study of chance in evolution explores Gillespie's proposed stochastic evolutionary force and sketches the implications of Gillespie's argument for philosophers' explorations of genetic drift.
Some people believe that there is an “explanatory gap” between the facts of physics and certain other facts about the world—for example, facts about consciousness. The gap is presented as a challenge to any thoroughgoing naturalism or physicalism. We believe that advocates of the explanatory gap have some reasonable expectations that cannot be merely dismissed. We also believe that naturalistic thinkers have the resources to close the explanatory gap, but that they have not adequately explained how and why these resources (...) work. In this paper we isolate the legitimate explanatory demands in the gap reasoning, as it is defended by Chalmers and Jackson . We then argue that these demands can be met. Our solution involves a novel proposal for understanding the relationship between theories, explanations, and scientific identities. (shrink)
Hull et al. make a direct connection between selection and replication. My view is that selection, at its causal crux, is not inherently connected to replication. I make plain the causal crux of selection, distinguishing it from replication. I discuss implications of my results for Hull et al.'s critique of Darden and Cain (1989).
The dissertation is a critical examination of theory evaluation in population genetics. There are three main philosophical approaches to theory evaluation in philosophy of science: confirmation and hypothesis testing, scientific change, and experimentation. Accounts that champion each of the main philosophical approaches to scientific theory evaluation are represented in philosophy of biology: confirmation and hypothesis testing by Elisabeth A. Lloyd, scientific change by Lindley Darden, and experimentation by David W. Rudge. I argue that each of the main approaches is insufficient (...) for evaluating population genetics theories. However, the accounts I critique are not fundamentally incompatible. I modify, unify, and extend them into a comprehensive account of theory evaluation for population genetics. ;My philosophical analysis is driven by a complex, important, and ongoing controversy in population genetics, viz., the R. A. Fisher-Sewall Wright controversy in population genetics. I use my historical case study to assess the adequacy of both the extant philosophical analyses of theory evaluation and my own account. Between 1929 and 1962 Fisher and Wright debated the main differences emanating from their alternative approaches to evolutionary theorizing. The debates between Fisher and Wright functionally ended with Fisher's death. However, Wright continued to clarify his position in the controversy until his death in 1988, and other biologists have continued work on the core debates. ;Recently, four scientific papers led by biologists Jerry A. Coyne and Michael J. Wade have been key in revisiting and rekindling the Fisher-Wright controversy with analyses of old theoretical and empirical issues as well as new developments that have spun off the older work. Four decades after the debates between Fisher and Wright, these papers have staked out, with substantial disagreement, claims about the evaluative status of the two predominant population genetics approaches to evolution in the field. A further task of this dissertation is to provide a non-partisan evaluation of the last 40 years of work on the controversy, i.e., the controversy since Fisher's death in 1962. It is hoped that such a critical analysis of the controversy will advance it to some extent. (shrink)
Charles Darwin was one of the ﬁrst to propose a uniﬁed framework with which to understand human and animal behavior. The foundation of Darwin’s framework is his theory of descent with modiﬁcation. What Darwin was convinced that theory allowed him to say about human and animal behavior is exempliﬁed in the ‘continuity thesis.’ As Darwin put it, ‘there is a much wider interval in mental power between one of the lowest ﬁshes, as a lamprey or lancelet, and one of the (...) higher apes, than between an ape and a man; yet this interval is ﬁlled up by numberless gradations’ (Darwin 1871 : 453). Darwin’s continuity thesis is the foundation of contemporary studies of animal behavior; it is, along with contemporary evolutionary theory, what uniﬁes the ﬁeld of animal behavior. (shrink)